In a cruel twist, the distressing information was being delivered to Mrs Eastwood around the same time as her excited husband was revealing in a live radio show that twins were on their way.

In a heart-rending interview in today's Belfast Telegraph, the seasoned politician held back tears as he told how he only learned what had happened when he later phoned his wife after participating in a televised pre-election leaders' debate.

"Not being there for Rachael at that really difficult time was what annoyed me most," he said.

"Rachael absolutely understood and she was very good about that, but I deeply regret it."

Mr Eastwood said the UTV debate, and an appearance on Radio Ulster's Talkback programme just prior to the TV show, were scheduled for the same day last February as his pregnant wife's 20-week scan.

Not having any reason to believe there was anything wrong with the unborn twins, it was decided that Rachel would have the routine scan in Londonderry while her husband travelled 75 miles to Belfast for his broadcast commitments.

But then came the bombshell news that one of the twins was already dead.

"We think we lost the baby at 13 or 14 weeks," said the 34-year-old Foyle MLA, who succeeded Alasdair McDonnell as SDLP leader three years ago.

"Rachael says she had a sense that there was something wrong but I don't know … there were no physical signs."

Eyes glistening with tears, Mr Eastwood said it's almost impossible to describe how he and Rachael balanced the profound pain of their loss with the joyful expectation of new life in the four months that followed.

"When we found out that we'd lost one of the twins it was a strange sort of experience because you're grieving for somebody you've never met," he said.

"It was doubly strange because I'd been on the radio talking about us expecting twins and people had been ringing in to congratulate me.

"After that programme, I went straight to UTV for the party leaders' debate, and Rachael couldn't contact me.

"I phoned her afterwards and that's when I found out."

He added: "It was very tough. It's hard to know what to think when something like that happens."

Mr Eastwood said he and 33-year-old Rachael - who already had a young daughter, Rosa, who's now two - dealt with their grief by focusing their energy on ensuring their unborn baby would be okay.

The Assembly member admitted that they were very concerned that something might happen to the surviving twin but, on June 29 last year, little Maya Olive, a fit and healthy baby girl, came into the world.

"What happened obviously plays on your mind ... but we were delighted when Maya was born," said Mr Eastwood.

"The consultants in Altnagelvin Hospital were fantastic. Rachael was actually brought in three weeks early because there were some issues with the baby's heartbeat, but it all ended up grand. She was able to have a natural birth.

"It's a strange thing when you're expecting twins and then a tragic episode happens, yet you still have this wonderful little baby."

Having told a radio audience that they were expecting twins back in February 2017, Mr Eastwood revealed that not everyone is aware of their subsequent tragedy.

He said: "The difficulty with us was that everything was very public. People still say to me, 'You had twins, how are they'?"

But Mr Eastwood added that, notwithstanding their sorrow, the shared trauma of losing one of the twins actually brought him and Rachael even closer.

"It binds you together," he said. "But the most important thing is that we have Rosa and little Maya ... we're blessed with what we have."